Various apparatus has been provided for making use of solar energy to do useful work. The patents to Green, Jr., U.S. Pat. No. 3,203,167, and Kyryluk, U.S. Pat. No. 3,514,942, show two such systems. Conventional attic ventilation systems make use of electrical power to run fans for removing hot air from the attic. In turn, cool outside air is drawn in through vents to replace the air removed by the attic fan.